It is, most definitely, one day at a time, one small step at a time.
I have two thoughts to get you on a better path:
1. His medication is likely not doing all it can or should. I would schedule an appointment with his prescribing doctor and try some changes.
2. Since your current parenting approach is not getting many positive results, it’s time to make a change. I HIGHLY recommend Ross Greene’s books, The Explosive Child and Raising Human Beings. Greene teaches parents that behavior is not the actual problem, only a symptom of the problem. The behavior is your child’s way of communicating something to you. Your job as the parent of a child with ADHD is to be a detective — find out WHY that behavior is occurring (the real problem) and address that. This approach changes our lives, and so many countless others.
Here’s more help:
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism